An element housing package for housing an element is provided with a base plate including a mounting region for mounting an element on a top surface of the base plate, a frame body disposed on the top surface of the base plate, a connector disposed on the inside and the outside of the frame body, a pedestal member positioned inside the frame body, and a wiring base plate to which the connector is electrically connected (refer to Japanese Unexamined Patent Application Publication No. 2003-309312A). Further, the wiring base plate is bonded to a top surface of the pedestal member with a bonding member placed therebetween.
In addition, in order to fix the position of the pedestal member on the inside of the element housing package, a side surface of the pedestal member is bonded to an inner surface of the frame body with a bonding member therebetween, and at the same time, a bottom surface of the pedestal member is bonded to the top surface of the base plate with a bonding member therebetween.
Here, in this type of the element housing package, during an assembly process of the element housing package and in an operation environment of the mounting structure, the base plate, the frame body, the pedestal member, and the wiring base plate are subject to heat applied from the outside of the element housing package, and also heat is generated from the element when the element is driven and the generated heat reaches the base plate, the frame body, the pedestal member, and the wiring base plate.
Therefore, as a result of temperature changes caused by an external environment of the element housing package, and temperature changes caused by the driving of the element, the base plate, the frame body, the pedestal member, and the wiring base plate thermally expand or thermally contract, and stress may occur due to differences in the thermal expansion coefficients of these members.
At that time, stress is easily applied to the pedestal member that is bonded to both the inner surface of the frame body and the top surface of the base plate, and there are cases in which the stress is concentrated on the top surface of the pedestal member. Therefore, significant stress is easily applied to the wiring base plate bonded to the top surface of the pedestal member, and cracks may occur in the wiring base plate and there may be a deterioration in the connection reliability of the wiring base plate and the connector.
In light of the above-described problem, an object of the present invention is to provide an element housing package that is capable of suppressing a deterioration in connection reliability of a wiring base plate and a connector.